Envelope fastener



May 8, 1934 J. w. FITZGERALD ENVELOPE FASTENER Filed Feb. l2, 1930gru/vento@ zggerald Patented May 8, 1934.-

UNTED STATES PATENT OFFICE ENVELOE FASTENER Application February 12,1930, Serial No. 427,812

1 Claim.

rilhis invention relates to envelope fasteners and it proposes a simpleand practical construction which while holding the envelope closed withcornplete security, acts as a tell-tale in response to 5 tampering withthe envelope, by breaking at an unexpected point in such manner as toleave the parts thereof irreparably separated.

The principal object of the invention is the provision of a fastener,particularly of the stud and l eyelet type in which the metal of thestud at some portion intermediate the top of the shank and the securingelement of the stud is ruptured or otherwise weakened in the manufactureof the stud in such manner that the shank of the stud will break offunder the strain attending the insertion of a knife or other instrumentbetween the stud and eyelet in the effort to unfasten these parts.

Other objects of the invention will appear as the following descriptionof a preferred and practical embodiment thereof proceeds.

In the drawing in which the same characters of reference are usedthroughout the several figures to denote identical parts:

Figure 1 is a plan View of the flap and of an envelope illustrating thebase portion of the stud;

Figure 2 is an underneath plan View of the same and of the envelope, thematerial of the envelope being broken away so as to disclose the top ofthe stud and the eyelet;

Figure 3 is an exploded View in perspective showing the stud and eyelet;

Figure 4 is a section taken along the line 4-4 of Figure 1;

Figure 5 is a section taken along the same line of the saine ligure, butshowing the parts in broken relation;

Figure 6 is a plan View on an enlarged scale of the base of the stud;and

Figure 7 is a plan View taken along the line 7-7 of Figure 5.

Referring now in detail to the several gures, the stud in general isindicated by the numeral 1, 2 representing in general the structure ofthe eyelet. The stud comprises a base portion 3 preferably formed withpointed lugs 4 by means of which it may be secured to the flap of anenvelope in the manner illustrated in Figure 1, by bending the lugs atright angles to the material of the envelope, piercing the envelope withthe downturned lugs and turning the lugs over on the inside of theenvelope in the manner indicated in Figure 5, the material of theenvelope being frictionally held beneath the inwardly turned lugs.

g Such means of securing a stud to an envelope is, of course, old and inthe present instance, the

shank 5 of the stud is directed inwardly between the flap and theadjacent side of the envelope.

The eyelet 2 is secured in a manner similar to that of the stud at theadjacent side of the envelope and in alignment with the stud, saideyelet being provided with lugs 6 similar to the lugs 4 on the stud.Said eyelet may be of any preferred construction, but as here shown, byway of example, the eyelet comprises a base portion 7 stamped to form achannel 8 thereby defining 5 a boss 9 in the form of an inverted cup.Said boss being formed at its center with an aperture 10 somewhatsmaller than the head 1l of the shank of the stud.

in order that the shank of the stud shall pass 7 through the aperture10, the Walls defining said aperture are made yielding or resilient, andradial slots 12 are formed in said walls, opening into said aperturedefining leaves 13 which are forced aside when the shank is forcedthrough said aperture, said leaves through their resiliency, spring backtoward their original position after the head of the shank has passedthrough said aperture so as to closely and frictionally engage saidshank.

The face of the aperture 10 is so related to the diameter of the shankthat when the latter is in place in said aperture, the leaves 13 cannotquite re-assume their original positions so that if it is attempted tounfasten the device by separating the stud from the eyelet, said leavesexert a toggle action against the sides of said shank or against theslight over-hang 14 which defines the head of said shank rendering theseparation 9o of these parts quite difficult, and only capable of beingaccomplished when some instrument is forced into the slots 12 and theparts violently pried. It is sometimes attempted to tamper with sealedmail in this manner, and, in the absence of the provision of the presentinvention, if the prying action is successful, it is quite possible torestore the parts to their original state with a little manipulation andthen to close the fastening device in the normal manner so that itbecomes dinicult or quite impossible to detect that the mail has beentampered with.

The present invention provides an inevitable tell-tale with respect tosuch tampering, inasmuch as the material from which the stud is made isweakened at some point between the lugs 4 by which the stud is securedto the envelope and the top 11 of the shank so that it will break apartat this point under a strain considerably less than any stress that canbe applied before the stud and eyelet may be separated at their point ofjuncture.

Figure 3 shows that the stud has been weakened adjacent the base of theshank as indicated at 15, the metal having been ruptured or partlybroken through along a circular line surrounding the shank of said stud.Trie weakened portion of the metal is clearly shown on a larger scale inFigure 4. The result of this weakening is that when the prying pressureis applied between the stud and eyelet, the shank of the stud willsuddenly break away as indicated in Figure 5, leaving the shank and theeyelet inseparably united and leaving the shank and the base of the studbroken apart in such a manner that they cannot be united.

This form of tell-tale is particularly effective, since the weakenedportion is perfectly inobvious to anyone upon casual inspection and fromthe fact that the parts when once broken away cannot be united.

A device of this character is particularly advantageous from thestandpoint of manufacture, since no more metal is required than inmanufacturing the ordinary forms of fastener in which this tell-talefeature is absent and no Variation in the steps of manufacture isrequired except the one simple step of bringing a die down upon the baseof the stud adjacent the shank for Weakening the metal to the desireddegree. While the stud is weakened to the extent that it will surelybreak off before sufcient pressure is applied between the stud andeyelet to separate these parts at their ordinary place of juncture, yetthe tenacity of the metal along the weakened portion is amply sufhcientto maintain the stud intact through the ordinary exigencies of use.

It Vis to be understood that while I have for purpose of illustrationshown a particular form of stud and eyelet, yet the specificconstruction of either of these parts is altogether immaterial to theinventive concept which concerns itself solely with the weakening of oneof the integral parts of the fastener in such a way that the saidintegral part will break in two at the place of weakening, thusperpetuating the opened condition of the envelope and giving evidence ofthe fact that it has been tampered with.

What I desire to claim as my invention is:

In an envelope fastener, a stud member comprising a plate with fasteningmeans thereon and a shank provided with an inwardly facing shoulder,there being `a weakened breaking portion between said means and saidshoulder, in combination with an eye member having a snap irremovablyengaging said shoulder.

JOHN W. FITZGERALD.

